This SAE Standard establishes the procedure for determining the operator duty cycle sound pressure level Lodc to which operators of powered recreational craft up to 24 m in length are exposed during typical operation as determined by marine engine duty cycle studies. This document describes the instrumentation, the required calibration procedures, the test site, the specifications for “standard craft”, the craft operating conditions, microphone positioning, test procedure, engine speeds for each of the Duty Cycle modes and the formula and table for calculating the Duty Cycle operator ear sound pressure level. This document is subject to change to keep pace with technical advances as well as other international standards and practices. Changes in this Revision: The sound pressure level measurements performed while applying this document are based on the Five-Mode Marine Engine Duty Cycle instead of a single engine speed. A calculation is required to obtain the Duty Cycle operator ear sound pressure level (Lodc). Provisions for type testing are provided along with specifications for Standard Craft. The original version of SAE J1281 provided only an estimate of operator exposure level and is outdated in terms of usefulness given new international legislation along with existing OSHA guidelines. The revised procedure has a broad range of applications with regard to domestic and international applications. Given the wide variety of craft/motor combinations the original procedure essentially implied that each and every craft/motor combination sold to the public should be tested to ensure compliance with noise exposure requirements/guidelines prior to marketing and sale of the craft to the public. Marine manufacturers are now required to certify the operator sound exposure level as specified by the Machinery Directive in the EU. Using this revised procedure manufacturers are provided with the means of establishing the actual sound exposure level in a “Standard Craft”. As a result, this procedure can be utilized to certify powered recreational craft in terms of operator sound exposure level prior to marketing and sale of the product. A manufacturer who certifies and publishes sound exposure data is essentially informing the public, including their customer base, of the actual sound pressure level to which an operator is exposed as a result of operating a specific marine propulsion system in a “Standard Craft”. Full disclosure of this data when in compliance with noise exposure guidelines/requirements can be a major benefit to the public safety and welfare.